Author's note: I forgot to add in the disclaimer last chapter that part of the concept for this story came from Aurilia's challenge, which I have also began writing if you want to check out Thicker Than Water.

Chapter Two: Blood is Thicker than Water

"All right, what's going on?" Albus Dumbledore said as he strode into the Hospital Wing.

Severus hurried over to him. "Albus, I need to talk to you. In private." There was a pause. "It's important."

"Severus, can't it wait?" Minerva said from behind him. "Harry Potter has D.M. We need to figure out -"

"Harry has Dissimilis Magus?" Albus asked, frowning.

"Yes," Severus said impatiently, "and what I have to say can help him. Trust me."

Albus nodded. "All right. Just give me a moment." He made his way over to Harry's bedside and looked down on his sleeping pupil. Harry's temperature was still far above normal, but he didn't look too fretful at the moment. Minerva was hovering with anxiety in her eyes, and Albus squeezed her hand gently and kissed her on the cheek in assurance before leaving with Severus.

"So, what is it you need to tell me, Severus?" Albus asked as he closed Poppy's office door behind them.

The Potions Master looked uncharacteristically flustered; he didn't seem able to keep his hands still, and when he spoke, there was both anxiety and hesitancy in his voice. "Albus. I have to confess, there are … certain facts that you are not aware of. Concerning the Dark Lord."

Albus frowned. "This has to do with Harry?"

"Apparently so." Severus sat down in Poppy's chair. "From the evidence out there, Albus, I was only conclude that Potter is adopted."

Albus blinked in surprise. "What makes you say that?"

"Poppy's file system is based on DNA. Whoever Potter's real parents are, it knows. When Minerva asked it for files relating to him, it threw out these."

Albus thumbed through the files Severus passed him. "So, the system is faulty. Nobody in the wizarding world is related closely enough to all of these people here."

"That's just it, Albus. There was. One baby boy, supposedly died twelve years ago."

Albus looked at Severus sharply. "Explain yourself, Severus."

Severus took a deep breath. "When the Dark Lord was at the height of his power, he performed many experiments. I don't know of most of them, and most of the ones I did know of I told you about." He paused. "But not this one."

Albus didn't speak, just continued regarding Severus with his piercing blue stare. Severus felt as if he was a student again, confessing to performing a particularly nasty jinx on the Marauders.

"He found this old spell to create life from magic donors, and used it. His plan was to use the child as a weapon, but he found his theory on stripping a human being of the ability to feel what he called "weak" emotions was no more than a theory, and demanded the child be killed. I thought he had been."

There was a pause before Albus spoke. "And you think Harry is the one."

"Bellatrix was his mother," Severus said. "She suffered from D.M. in the past, and I know her sisters both have the gene too. It's one of them you want for the potion. As for his paternity, well, not all the donors knew their DNA was taken for this." Severus met Albus' eyes guiltily. "I took yours. Mine was also used and the Dark Lord's himself and Remus'."

"Let me get this straight. Are you telling me that – Harry is …"

"Technically, he's your son, Albus. And also, technically, mine, and Remus', and the Dark Lord's. As well as Bellatrix's."

Albus couldn't speak for several minutes. Severus sighed.

"Look Albus, I'm sorry I didn't tell you before. But Remus and I had made a plan to get him away from the Dark Lord and raise him ourselves, and – I was afraid that you would want to take a different course of action. And then when Bellatrix supposedly killed him, there seemed no point." Severus stood. "I know this is a shock, it is to me too, but perhaps you ought to work on getting some blood for that potion."

Andromeda Tonks was woken early by the doorbell. Stumbling downstairs in her dressing-gown, she saw it was barely six o'clock and wondered who on earth was calling.

"Good morning, Andromeda."

She blinked a few times. "Er, morning, Professor Dumbledore. Can I help you?" Albus looked more grave than cheery, and her heart missed a beat. "Has something happened to my Dora?"

"Oh, no, nothing like that," Albus assured her. "I wonder … Could I?"

"Yes, yes, come in." Andromeda stepped aside to allow him into the house. "You'll have to excuse the get-up, it's very early."

"I realise that, and I apologise," Albus said, "but it is a matter of great importance, Andromeda."

"About what?" Andromeda led Albus into the kitchen. "Tea? Coffee?"

"Tea would be lovely." Albus paused. "Your sister, Bellatrix. Were you aware that she had a son?"

Andromeda nearly dropped the kettle. "Bella what?"

"Well, that was more of a rhetorical question really I suppose. I did not expect you knew. It seems those who did know were under the impression that he was dead. Until now, that is."

Andromeda sat down slowly at the kitchen table, the tea forgotten. "So … I have another nephew?"

"Yes, you do." Some of the twinkle came back into Albus' eye. "He is a truly remarkable boy. But -" The twinkle disappeared again. "- He's ill with D.M." Andromeda looked up sharply. "That is how we found out who he was. He does not even know at this point. Right now, the priority is to get him better. I believe you're familiar with the potion?"

Andromeda nodded. "You can have my blood, as much of it as you need."

"He will appreciate it, I'm sure."

"What's his name?" she asked.

The answer left her speechless. "Harry Potter."

As Harry started to wake up, he groaned. His head felt like it was splitting open, and he was shivering madly even though he was uncomfortably hot. He vaguely heard movement around him, and felt a hand squeeze his gently. "Harry? Are you awake?"

"Mm." He started to open his eyes, wincing at the bright whiteness of the Hospital Wing. The voice who had spoken was not familiar, and he squinted, trying to work out who was sitting beside him.

A woman slowly came into focus. She looked probably in her late thirties, with mouse-brown hair and pale skin. She smiled warmly at him when he met her eyes. "Hello, Harry. How are you feeling?"

Harry coughed. "Not good."

"My name's Andromeda Tonks." She brushed his fringe out of his eyes. "You can call me Auntie Andie if you like. Or just Andie if you prefer, I have no objections."

"Um." Harry frowned, confused. "Why would I call you Auntie? I don't know you."

"Well, according to Professor Dumbledore, I am your aunt." Harry's eyes widened, and she nodded. "Yes. He said you've always been told that you had no magical relatives, but it appears that you actually do. Nobody knew until now."

The headache forgotten, Harry stammered, "I-I've got relatives other than the Dursleys?"

"A fair few, it seems." Andromeda kissed him gently on the forehead. "But we can talk about them later. Just focus on getting better for now, all right?"

"Okay." Harry couldn't believe it. He had other relatives, ones who cared about him – at least, this one did.

"Harry." Andromeda's tone was more serious now. "You are very ill. Madam Pomfrey can explain better than I can, but you're going to have to take a potion to get better. It's being made as we speak, so try not to worry, all right?"

"I'll try," Harry promised.

"She's going to tell you what's wrong now," Andromeda soothed. "I'll leave you to talk with her, but I'll come back in a little while, okay?"

Harry nodded. "Okay. Thank you," he whispered.

His head was spinning as she left. He didn't want her to go. The only family he knew cared about him, and she was leaving him to the strict matron.

Although Madam Pomfrey kept her tone business-like as she spoke to him, there was more softness in her eyes than usual. "Harry, you have a condition called Dissimilis Magus - D.M. for short."

"What is it?" Harry asked.

"It means that you have an imbalance of the magic cells in your body. There are many different kinds of magic cells," Madam Pomfrey explained. "Anyone with the disorder has more of some than others. It's not life-threatening in itself, you can live a perfectly normal life not even aware of it, but sometimes the majority cells can decide that the minority cells are a threat, and begin to multiply very quickly and attack them."

"So that's what's happening to me?"

She nodded. "Yes."

"And it's life-threatening."

"Yes. Even though having half your magic cells will not kill you – your magic would just be irratic – the cells don't stop there; they start attacking everything."

"Andie said you had a potion for me. Does that cure it?"

"It doesn't get rid of the D.M, but it does revert your cells back to the way they were."

Harry thought a moment. "Does that mean I can get ill again?"

"It is a possibility, but now we know you have the disorder, precautions can be taken."

"Okay, here we are." Hermione dropped a heavy book down on the library table. "Dissimilis Magus."

Ron eyed the page. "That's definitely what Madam Pomfrey said?"

She nodded. "I've heard of it, but wasn't sure exactly what it was."

"Ditto. So, what is it?"

Hermione perused the page. "Basically, some of Harry's magic cells are attacking the others."

"That can't be good. How's it cured?" Ron paused, an uncomfortable thought striking him. "Harry will be cured, right?"

"Yes, there's a potion – containing – oh."

"I don't like the sound of that."

"It needs the blood of a relative with the gene."

"Yuck, that's gross – Oh. I get your point." Ron considered. "Couldn't they use one of the Dursleys?"

Hermione shook her head. "No, Muggles can't get it. They don't have enough magic cells in them."

"I didn't know they had any."

"Everyone has some, the difference between Muggles and wizards is that wizards have enough to be able to use a wand. Magic cells can't be picked up by Muggle technology. But that's not the point. Any wizard who has the gene also has the condition, because it's a dominant gene – like having brown eyes. So the Dursleys' blood would be useless."

"Why can't they use the blood of someone else with the condition? Why does it have to be a relative?"

"Because there's an almost infinite number of variations, Ron. The only way to guarantee that the donor has the same as you is to use a relative. Otherwise – you would just die faster."

Ron shuddered. "So Harry's going to die." His voice was suddenly hollow.

Hermione shook her head. "No, there must be something. Madam Pomfrey made it sound like they were working on something." Ron brightened slightly. "We just have to hope they succeed."